diff --git a/.buildkite/pipelines/intake.yml b/.buildkite/pipelines/intake.yml
index fcda5d1ff436..14cda6e2be7d 100644
--- a/.buildkite/pipelines/intake.yml
+++ b/.buildkite/pipelines/intake.yml
@@ -57,6 +57,7 @@ steps:
       image: family/elasticsearch-ubuntu-2004
       machineType: n1-standard-32
       buildDirectory: /dev/shm/bk
+
   - group: bwc-snapshots
     steps:
       - label: "{{matrix.BWC_VERSION}} / bwc-snapshots"
@@ -64,7 +65,7 @@ steps:
         timeout_in_minutes: 300
         matrix:
           setup:
-            BWC_VERSION: ["8.17.8", "8.18.3", "8.19.0", "9.0.3", "9.1.0"]
+            BWC_VERSION: ["8.17.9", "8.18.3", "8.19.0", "9.0.3", "9.1.0"]
         agents:
           provider: gcp
           image: family/elasticsearch-ubuntu-2404
@@ -74,9 +75,6 @@ steps:
           BWC_VERSION: "{{matrix.BWC_VERSION}}"
   - label: bc-upgrade
     command: ".buildkite/scripts/run-bc-upgrade-tests.sh"
-    agents:
-      image: "docker.elastic.co/ci-agent-images/eck-region/buildkite-agent:1.5"
-      memory: "4G"
   - group: lucene-compat
     steps:
       - label: "{{matrix.LUCENE_VERSION}} / lucene-compat"
diff --git a/.buildkite/pipelines/periodic-packaging.yml b/.buildkite/pipelines/periodic-packaging.yml
index 34d3ecaa9c5f..77ed899353dd 100644
--- a/.buildkite/pipelines/periodic-packaging.yml
+++ b/.buildkite/pipelines/periodic-packaging.yml
@@ -302,8 +302,8 @@ steps:
         env:
           BWC_VERSION: 8.16.6
 
-      - label: "{{matrix.image}} / 8.17.8 / packaging-tests-upgrade"
-        command: ./.ci/scripts/packaging-test.sh -Dbwc.checkout.align=true destructiveDistroUpgradeTest.v8.17.8
+      - label: "{{matrix.image}} / 8.17.9 / packaging-tests-upgrade"
+        command: ./.ci/scripts/packaging-test.sh -Dbwc.checkout.align=true destructiveDistroUpgradeTest.v8.17.9
         timeout_in_minutes: 300
         matrix:
           setup:
@@ -316,7 +316,7 @@ steps:
           machineType: custom-16-32768
           buildDirectory: /dev/shm/bk
         env:
-          BWC_VERSION: 8.17.8
+          BWC_VERSION: 8.17.9
 
       - label: "{{matrix.image}} / 8.18.3 / packaging-tests-upgrade"
         command: ./.ci/scripts/packaging-test.sh -Dbwc.checkout.align=true destructiveDistroUpgradeTest.v8.18.3
diff --git a/.buildkite/pipelines/periodic.yml b/.buildkite/pipelines/periodic.yml
index 75bf9d701f4c..3d25ec600427 100644
--- a/.buildkite/pipelines/periodic.yml
+++ b/.buildkite/pipelines/periodic.yml
@@ -325,8 +325,8 @@ steps:
             - signal_reason: agent_stop
               limit: 3
 
-      - label: 8.17.8 / bwc
-        command: .ci/scripts/run-gradle.sh -Dbwc.checkout.align=true v8.17.8#bwcTest
+      - label: 8.17.9 / bwc
+        command: .ci/scripts/run-gradle.sh -Dbwc.checkout.align=true v8.17.9#bwcTest
         timeout_in_minutes: 300
         agents:
           provider: gcp
@@ -335,7 +335,7 @@ steps:
           buildDirectory: /dev/shm/bk
           preemptible: true
         env:
-          BWC_VERSION: 8.17.8
+          BWC_VERSION: 8.17.9
         retry:
           automatic:
             - exit_status: "-1"
@@ -487,7 +487,7 @@ steps:
           setup:
             ES_RUNTIME_JAVA:
               - openjdk21
-            BWC_VERSION: ["8.17.8", "8.18.3", "8.19.0", "9.0.3", "9.1.0"]
+            BWC_VERSION: ["8.17.9", "8.18.3", "8.19.0", "9.0.3", "9.1.0"]
         agents:
           provider: gcp
           image: family/elasticsearch-ubuntu-2404
@@ -531,7 +531,7 @@ steps:
             ES_RUNTIME_JAVA:
               - openjdk21
               - openjdk23
-            BWC_VERSION: ["8.17.8", "8.18.3", "8.19.0", "9.0.3", "9.1.0"]
+            BWC_VERSION: ["8.17.9", "8.18.3", "8.19.0", "9.0.3", "9.1.0"]
         agents:
           provider: gcp
           image: family/elasticsearch-ubuntu-2404
diff --git a/.ci/bwcVersions b/.ci/bwcVersions
index c45ceeed0ad1..bb084e5c6136 100644
--- a/.ci/bwcVersions
+++ b/.ci/bwcVersions
@@ -16,7 +16,7 @@ BWC_VERSION:
   - "8.14.3"
   - "8.15.5"
   - "8.16.6"
-  - "8.17.8"
+  - "8.17.9"
   - "8.18.3"
   - "8.19.0"
   - "9.0.3"
diff --git a/.ci/snapshotBwcVersions b/.ci/snapshotBwcVersions
index 6c37e7efea22..5f513799bc8d 100644
--- a/.ci/snapshotBwcVersions
+++ b/.ci/snapshotBwcVersions
@@ -1,5 +1,5 @@
 BWC_VERSION:
-  - "8.17.8"
+  - "8.17.9"
   - "8.18.3"
   - "8.19.0"
   - "9.0.3"
diff --git a/server/src/main/java/org/elasticsearch/TransportVersions.java b/server/src/main/java/org/elasticsearch/TransportVersions.java
index 98204a750b77..736db54e07d1 100644
--- a/server/src/main/java/org/elasticsearch/TransportVersions.java
+++ b/server/src/main/java/org/elasticsearch/TransportVersions.java
@@ -98,6 +98,7 @@ public class TransportVersions {
     public static final TransportVersion INITIAL_ELASTICSEARCH_8_17_6 = def(8_797_0_06);
     public static final TransportVersion INITIAL_ELASTICSEARCH_8_17_7 = def(8_797_0_07);
     public static final TransportVersion INITIAL_ELASTICSEARCH_8_17_8 = def(8_797_0_08);
+    public static final TransportVersion INITIAL_ELASTICSEARCH_8_17_9 = def(8_797_0_09);
     public static final TransportVersion INDEXING_PRESSURE_THROTTLING_STATS = def(8_798_0_00);
     public static final TransportVersion REINDEX_DATA_STREAMS = def(8_799_0_00);
     public static final TransportVersion ESQL_REMOVE_NODE_LEVEL_PLAN = def(8_800_0_00);
diff --git a/server/src/main/java/org/elasticsearch/Version.java b/server/src/main/java/org/elasticsearch/Version.java
index ac1264309f72..f5a9233b858f 100644
--- a/server/src/main/java/org/elasticsearch/Version.java
+++ b/server/src/main/java/org/elasticsearch/Version.java
@@ -204,6 +204,7 @@ public class Version implements VersionId<Version>, ToXContentFragment {
     public static final Version V_8_17_6 = new Version(8_17_06_99);
     public static final Version V_8_17_7 = new Version(8_17_07_99);
     public static final Version V_8_17_8 = new Version(8_17_08_99);
+    public static final Version V_8_17_9 = new Version(8_17_09_99);
     public static final Version V_8_18_0 = new Version(8_18_00_99);
     public static final Version V_8_18_1 = new Version(8_18_01_99);
     public static final Version V_8_18_2 = new Version(8_18_02_99);
diff --git a/server/src/main/resources/org/elasticsearch/TransportVersions.csv b/server/src/main/resources/org/elasticsearch/TransportVersions.csv
index b9ac86af98dd..1785fc60d072 100644
--- a/server/src/main/resources/org/elasticsearch/TransportVersions.csv
+++ b/server/src/main/resources/org/elasticsearch/TransportVersions.csv
@@ -148,6 +148,7 @@
 8.17.5,8797005
 8.17.6,8797006
 8.17.7,8797007
+8.17.8,8797008
 8.18.0,8840002
 8.18.1,8840003
 8.18.2,8840004
diff --git a/server/src/main/resources/org/elasticsearch/index/IndexVersions.csv b/server/src/main/resources/org/elasticsearch/index/IndexVersions.csv
index 81046f66e7c9..8064b77d3ce1 100644
--- a/server/src/main/resources/org/elasticsearch/index/IndexVersions.csv
+++ b/server/src/main/resources/org/elasticsearch/index/IndexVersions.csv
@@ -148,6 +148,7 @@
 8.17.5,8521000
 8.17.6,8521000
 8.17.7,8521000
+8.17.8,8521000
 8.18.0,8525000
 8.18.1,8525000
 8.18.2,8525000